Drop generic parameters from FunctionImpl classes in JVM runtime

They are not used in any way but cause some complex code in JVM back-end

core/runtime.jvm/src/kotlin/jvm/internal/ExtensionFunctionImpl.kt

@@ -18,6 +18,6 @@ package kotlin.jvm.internal
 
 import java.io.Serializable
 
-public abstract class ExtensionFunctionImpl<in T, out R> : Serializable {
+public abstract class ExtensionFunctionImpl : Serializable {
     override fun toString() = "${(this as Object).getClass().getGenericInterfaces()[0]}"
 }

core/runtime.jvm/src/kotlin/jvm/internal/FunctionImpl.kt

@@ -18,6 +18,6 @@ package kotlin.jvm.internal
 
 import java.io.Serializable
 
-public abstract class FunctionImpl<out R> : Serializable {
+public abstract class FunctionImpl : Serializable {
     override fun toString() = "${(this as Object).getClass().getGenericInterfaces()[0]}"
 }

core/runtime.jvm/src/kotlin/jvm/internal/MemberFunctionImpl.kt

@@ -18,6 +18,6 @@ package kotlin.jvm.internal
 
 import java.io.Serializable
 
-public abstract class MemberFunctionImpl<in T, out R> : Serializable {
+public abstract class MemberFunctionImpl : Serializable {
     override fun toString() = "${(this as Object).getClass().getGenericInterfaces()[0]}"
 }